1. Field of the Invention
The present invention relates to a human cooperation robot system in which a robot is caused to perform a retreat operation depending on an external force acting on the robot.
2. Description of the Related Art
In recent years, a human cooperation robot system has been developed in which a human and a robot are deployed in a mixed manner in a production site and a production operation is divided up between the human and the robot. In some cases, a safety fence is provided between a human and a robot in order to secure the human's safety. However, providing a safety fence could lead to a delay in the operation; therefore, there has recently been proposed a human cooperation robot system in which no safety fence is used.
In such a human cooperation robot system, when the robot approaches or comes into contact with a human, the robot is decelerated or stopped in order to secure the human's safety. However, since the human and the robot share the operation area, a case may occur in which the decelerated or stopped robot constitutes an obstacle when the human carries out an operation.
Thus, it is desired that such a robot be retreated from the operation area. Therefore, the robot is provided with a sensor that detects an external force imparted to the robot when the human pushes the robot. In this manner, the robot is caused to perform a retreat operation simply by the human pushing the robot with an external force larger than or equal to a predetermined value. In this instance, there is no need to use a teaching operation panel.
In Japanese Patent No. 4,445,038 Publication, in a system in which a human and a robot convey a workpiece in cooperation with each other, there is provided a sensor that detects an external force acting between the workpiece and a hand of the robot. In Japanese Patent Laid-open Publication No. H10-291182, a configuration is disclosed in which a torque sensor is provided between a motor and an arm driven by the motor.